17 replies to this topic

[rookie1ja]

Pouring water V. - Back to the Water and Weighing Puzzles
Measure exactly 2 liters of water if you have:
1. 4 and 5-liter bowls
2. 4 and 3-liter bowls

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Spoiler for Solution

Pouring Water V. - solution
1st Fill the 5-litre bowl, overspill water from it to fill the 4-litre bowl, which you empty afterwards. Overspill the remaining 1 litre to the 4-litre bowl. Refill the 5-litre bowl and overspill water from it to fill the 4-litre bowl (where there is already 1 litre). Thus you are left with 2 litres in the 5-litre bowl.
2nd The same principle – this time from the other end. Fill the 3-litre bowl and overspill all of the water to the 4-litre bowl. Refill the 3-litre bowl and fill the 4-litre bowl to the top. And there you have 2 litres in the 3-litre bowl.

[fosley]

You can solve both sets of buckets from both small-to-big and big-to-small. The green water is your solution, and the blue water is the alternate solution. My first solutions were the green solution for the 5/4 set and the blue solution for the 4/3 set. In both cases, your solution is faster, but I thought it interesting to note that you can do it either way.

Attached Images

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[rookie1ja]

Good picture - speaks more than a thousand words

[coolastro1016]

fill the 5 liter up and pour it in the 3 liter. The over flow is 2 liters.
There are many ways to solve this one.

[islek2007]

coolastro1016,
im new here but the problem clearly states two different problems so using the 5 and 3 liters is impossible since they arent on the same problem together

[geekygirl]

Both cases have a 4 litre bucket. If you fill the bucket and then slowly empty it until the water is touch just touching one side of the top and is just barely touching all of the bottom, you have the bucket half filled and therefore 2 litres. Basically, picture cutting the bucket diagonally.

[Martini]

Both cases have a 4 litre bucket. If you fill the bucket and then slowly empty it until the water is touch just touching one side of the top and is just barely touching all of the bottom, you have the bucket half filled and therefore 2 litres. Basically, picture cutting the bucket diagonally.

Excellent answer! Almost all buckets are symmetrical, so this will work.

[skbrown]

Both cases have a 4 litre bucket. If you fill the bucket and then slowly empty it until the water is touch just touching one side of the top and is just barely touching all of the bottom, you have the bucket half filled and therefore 2 litres. Basically, picture cutting the bucket diagonally.

Er, most buckets are tapered, aren't they?, and so this would not work at all. Or have I misunderstood your suggestion?

[Martini]

Both cases have a 4 litre bucket. If you fill the bucket and then slowly empty it until the water is touch just touching one side of the top and is just barely touching all of the bottom, you have the bucket half filled and therefore 2 litres. Basically, picture cutting the bucket diagonally.

Er, most buckets are tapered, aren't they?, and so this would not work at all. Or have I misunderstood your suggestion?

You haven't misunderstood; you're just under the assumption that skbrown's solution won't work with a tapered bucket. It will, as long as it's symmetrical.

[hoopshank]

Both cases have a 4 litre bucket. If you fill the bucket and then slowly empty it until the water is touch just touching one side of the top and is just barely touching all of the bottom, you have the bucket half filled and therefore 2 litres. Basically, picture cutting the bucket diagonally.

Er, most buckets are tapered, aren't they?, and so this would not work at all. Or have I misunderstood your suggestion?

You haven't misunderstood; you're just under the assumption that skbrown's solution won't work with a tapered bucket. It will, as long as it's symmetrical.

This is not true! If it were a cylinder it would work. If it's tapered, it will not. Consider the extreme example of a bucket tapered to a point - you get a cone. How do you know when to stop pouring? Besides, we have BOWLS not buckets, which suggests an entirely different shape to me. Symmetrical or not, this method does not work with standard bowl or bucket shapes.